U.S. patent number 4,948,317 [Application Number 07/345,310] was granted by the patent office on 1990-08-14 for method and device for electrical fitting stabilization.
Invention is credited to Carl Marinaro.
United States Patent |
4,948,317 |
Marinaro |
August 14, 1990 |
Method and device for electrical fitting stabilization
Abstract
For mounting a dual socket switch, or similar electrical fitting
or accessory to a junction box, a method of stabilizing the
mounting and a deformable shim adapted for slidable securement, one
on each of two mounting screws, for pressed deformation between the
fitting and the junction box to thereby rigidify the fitting in its
attachment to the junction box as an incidence of the fitting's
installation.
Inventors: |
Marinaro; Carl (Butler,
PA) |
Family
ID: |
23354509 |
Appl.
No.: |
07/345,310 |
Filed: |
May 1, 1989 |
Current U.S.
Class: |
411/535; 220/3.7;
411/547; 439/539 |
Current CPC
Class: |
F16B
43/00 (20130101); H02G 3/18 (20130101) |
Current International
Class: |
F16B
43/00 (20060101); H02G 3/18 (20060101); F16B
043/00 (); H02G 003/08 () |
Field of
Search: |
;411/523,524,535,536,547
;439/539,569 ;220/3.3,3.4,3.5,3.7,3.8 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Wilson; Neill R.
Attorney, Agent or Firm: Atwell; George C.
Claims
I claim:
1. A deformable shim for slidable securement on the shank of a
mounting screw of an electrical accessory, between a mounting tab
of the accessory and a utility box, including:
a body member having oppositely-facing first and second
spaced-apart bearing surfaces;
the body member having integral deformable means interconnecting
the bearing surfaces; and
the deformable means being adapted to defrom generally inwardly
toward the screw shank in response to force applied equally against
the bearing surfaces by inward manipulation of the mounting screw
as an incident of installing the accessory on the utility box.
2. The shim of claim 1 wherein each bearing surface defines an
opening therethrough to accommodate disposition through the body
member of the mounting screw.
3. The shim of claim 1 wherein the deformable means is an
intermediate body portion extending generally between the bearing
surfaces.
4. The shim of claim 3 wherein the intermediate body portion
extends from an edge of the first bearing surface generally
diagonally and through the plane of extension of the mounting screw
to an edge of the second bearing surface.
5. The shim of claim 3 wherein the intermediate body portion
defines an elongated slot.
6. The shim of claim 1 further comprising an integral deformable
flange extending from each bearing surface and generally toward the
other bearing surface.
7. The shim of claim 1 wherein the shim is elastically
deformable.
8. For an assembly including an electrical receptacle mounted on a
utility box wherein the receptacle is of the type having
oppositely-projecting ears with respect to holes for accommodating
mounting screws for fastening the receptacle to the box, a device
for stabilizing the receptacle in relation to the box
comprising:
a V-shaped clip with a pair of legs adapted for placement on the
screw between the ear and the box;
means on the clip promoting its retention on one of the screws;
the clip being resitent to deformation but deformable between the
ear and the box when the ear is drawn toward the box by
manipulation of the screw on which it is retained;
a hole in each leg of substantially the same diameter as the shank
of the mounting screw;
the slot merging with the holes and gradually narrowing toward the
holes;
the point of merger with the slot of each hole being at the
narrowest part of the slot; and
the width of the narrowest part being less than the mounting screw
diameter.
9. A shim for stabilizing an electrical accessory to a utility box,
having spaced-apart oppositely-facing and generally parallel
bearing surfaces;
each bearing surface defining an aperture aligned one with the
other to accommodate extension therethrough of a mounting
screw;
normally rigid means separating the bearing surfaces and adapted to
yieldably deform inwardly toward the mounting screw when a
compressive force is applied to squeeze the bearing surfaces toward
each other.
Description
BACKGROUND OF THE INVENTION
This invention relates generally to fitting or accessory
installation in an electrical junction box, and more particularly
pertains to means for obtaining a secure stabilized placement of
the fitting in the junction box.
In new building and home construction, it is common practice, once
structural framing is completed, for the electrician to place
electrical outlet and switch utility boxes pursuant to plan and
then run electrical cables to the boxes prior to installation of
lathe and plaster or plasterboard or other interior wall surface
material. Ideally, when the electrician returns to complete his
work by installation of the socket fittings and switches, etc, he
needs only to complete the connection of the exposed cable ends,
protruding from each utility box, to the fitting, then install the
fitting in place within the utility box, prior to affixing the
appropriate appearance cover plate. Such work can be quickly and
uniformly accomplished if the forward edge of the utility box is in
vertical alignment with the wall surface, however, there is often
misalignment due to a twisted or bowed condition of the stud to
which the utility box is mounted. Also, even when the degree of
misalignment is not excessive, there is often the additional
problem caused by the excessived size of the wall surface opening
which surrounds the utility box. This problem is prevalent where
plasterboard installer use a router to rough out an opening in a
plasterboard wall surface to generally coincide with the utility
box position.
In any of the situtations heretofore described, the electrician
must fasten an accessory or fitting, such as a dual socket or
switch, in the utility box, leaving the mounting screws in an
unseated position whereby the fitting "floats" on the box.
Stabilization of the fitting then may depend upon the oppositely
extending metal ears of the fitting abutting against the wall
surface. Where the opening about the box is too large whereby the
ears will not reach the wall surface, stabilization becomes a
matter of pulling the fitting into proper aligned position by means
of the attachment of the appearance cover plate, and the fitting
nevertheless often remains loose relative to the utility box.
Stabilization by pressure of the peripheral undersurface of the
cover plate against the wall surface is often only temporary since
the strain on the cover plate will often distort or fracture the
plate either as an incidence of its installation or at a later
time. One corrective measure has been to provide cover plates
formed from high-strength and comparatively expensive plastic such
as polycarbonate which is comparatively resistant to strain
fracture. Limited shifting of the fitting in a vertical plane may
still occur even where the integrity of the cover plate is assured
by the strength of its composition. In any event, if a fitting is
able to shift relative to the utility box, the electric cable or
wire end connections to the fitting are flexed each time the
fitting is caused to move relative to the box, thus creating a fire
hazard if the wire breaks or works loose and results in current
arcing. Where the fitting is a dual socket, the insertion and
withdrawal of plugs moves the fitting against its wire connections,
running the risk of eventual wire severance. Where the fitting is a
switch assembly with a toggle or dimmer dial, an undesirable
shifting of the fitting can occur each time manual force is applied
to manipulate the switch.
The foregoing problems have been recognized and previously
addressed by various means in the prior art. For the situation
where the utility box is disposed backwardly from the wall surface
and the opening in the wall surface about the utility box is
excessive, an oversize appearance cover plate has been provided for
use in combination with a back-up flat sheet metal shim plate. This
approach creates a stabilizing tension between the fitting and the
wall surface but does not entirely solve the problem of the
floating fitting and its tendency to shift relative to the utility
box due to the unseated mounting screws.
In addition to the commercially introduced devices which have been
made available over the years to achieve stabilization of an
electrical fitting with a utility box, various on-site means are
often employed by innovative electricians to compensate for
situations where utility boxes are mounted in misaligned
orientation and to achieve firm attachment of electrical fittings
to such boxes. It is not uncommon to employ multiple washers on the
mounting screw between the fitting ear and the utility box or to
jam pieces of cardboard or plastic onto the screw shank in order to
fill the void between the fitting ear and the box and thus shim the
connection. Plastic tabs have, in fact, been made commercially
available for this purpose. Such tabs, whether used singly or in
plural stacks, have the disadvantage of permanent deformation which
generally results in later loosening of the connection.
One early attempt to solve the aforedescribed problems is found in
U.S. Pat. No. 2,291,107 wherein socket supporting elements, in the
form of a pair of transversely extending shim plates, are provided
to be carried on the utility box mounting screw with opposite ends
extending laterally to overlie the wall surface beneath the
appearance cover plate. The structure of this invention depends on
stabilizing the fitting to the wall surface but does not address
stabilization of the fitting directly to its junction box.
SUMMARY OF THE INVENTION
This invention comprehends a means to attach an accessory or a
fitting, such as a dual receptacle, switch, or the like, to an
electrical junction box whereby the fitting can be properly aligned
with the adjacent wall surface even though the junction box may not
be properly aligned relative to the wall surface such that abutment
mounting of the fitting to the junction box is inconsistent with
wall surface alignment.
The structure of the invention, for practicing the method herein
disclosed, may take one of several forms, comprising a deformable
shim or spacer for slidable securement on the mounting screw of an
electrical accessory to be attached to a utility box. In one
preferred form, the structure of the invention comprises a normally
substantially rigid body member having oppositely-facing first and
second bearing surfaces and an intermediate integral connecting
body portion extending between the bearing surfaces. The
intermediate body portion is deformable in response to force
applied equally against the bearing surfaces by the inward
manipulation of the mounting screw as an incident of installing the
accessory or fitting on the utility box. The shim may be formed
from sheet metal or plastic and it is preferred that it has some
degree of elasticity although its most critical characteristic is
its capability of gradual compressive deformation.
It is a primary objective of the method and structure herein
disclosed to provide a means of stabilizing the connection of an
electrical accessory or fitting to an electrical junction box
whereby the fitting or accessory will be permanently held in a
fixed position relative to the utility box and in proper alignment
with the adjacent wall surface, particularly in an instance where
the utility box may be misaligned relative to the wall surface. The
term "wall surface" is, for the purpose of this disclosure, given a
board generic meaning to include a wall, floor, or ceiling surface
where an opening may be provided to accommodate installation of a
utility or junction box in the construction or remodeling of a
building or housing structure.
Details of the method of this invention and the several embodiments
of the invention structure will be best understood from the ensuing
description when read with reference to the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a shim device in accordance with
the present invention, shown at an intermediate stage of its
manufacture and prior to its final formation;
FIG. 2 is an exploded view of certain electrical components and
further illustrating the shim device first shown in FIG. 1 formed
for use in cooperation with the illustrated electrical
components;
FIG. 3 is a elevational view in partial vertical section
illustrating the shim device shown in FIGS. 1 and 2 in its intended
installed position;
FIG. 4A is a perspective view illustrating a modified form of the
structure first shown in FIG. 1;
FIG. 4B is a perspective view of the final form of the structure
first shown in FIG. 4A;
FIG. 5 is an exploded perspective view of certain electrical
components in combination with a second embodiment of a shim device
in accordance with the present invention;
FIG. 6 is a perspective view of an electrical fitting wherein an
embodiment of a shim device structure in accordance with the
present invention is an integral part of the fitting; and
FIG. 7 is a perspective view of still another embodiment of a
device in accordance with the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
In FIG. 1 there in shown a shim device 10 which in the initial
stage of its manufacture comprises a flat planar elongated member
12. Described transversely across the surface of the member 12 are
break lines 14, 16, 18, and 20. Defined between break lines 16 and
18 is an intermediate body section 22 and it is flanked by opposite
respective sections 24 and 26, which are respectively defined by
break lines 14 and 16, and 18 and 20. The central section 22
defines an elongated slot 28, and the sections 24 and 26
respectively define apertures or openings 30 and 32. At the
opposite ends of the member 12 are notches 34 and 36 which
respectively separate legs 38 and 40, and 42 and 44.
In the last step of its manufacture, the device 10 is foldably
formed, by folding it along the aforementioned break lines, to its
configuration as shown in FIG. 2. Also known in FIG. 2 is an
electrical utility box 50 having tabs 52 and 54 with respective
threaded holes 56 and 58. FIG. 2 further illustrates an electrical
fitting or receptacle 60 having mounting ears 62 and 64 with
respective holes 66 and 68 for accommodating mounting screws 70 and
72.
In electrical wiring installation, the utility box 50 would be
suitably mounted on a stud or similar frame member with wire ends
protruding from the open face of the box (not shown) for
appropriate connection to the fitting 60 after which the fitting 60
would be installed with its major body portion within the box and
its face, the dual receptacle arrangement, across the face of the
box. Typically, screws such as the screws 70 and 72 are inserted
through the openings 66 and 68 and threadably secured in the
openings 56 and 58 of the tabs 52 and 54.
In the ideal situation, box 50 would be mounted on its supporting
stud whereby its forward edge would be in both vertical and
horizontal alignment with the outer surface or wallboard or similar
wall surface finishing material. Then, proper installation of the
fitting 60 would draw the ears 62 and 64 firmly against the tabs 52
and 54. Protruding portions 74 and 76 of receptacle 60 would then
be in position for installation of, and aligned registration with,
a typical appearance cover plate (not shown) to complete the
installation.
The aforedescribed installation, where proper alignment between the
various electrical components and the wall surface is obtained, is
not consistently obtained in practice, often due to a twisted or
bowed stud to which the utility box is mounted or an uneven outer
surface on the stud to which the wall surface conforms. In such
situtations, it is common, where conditions permit, to fasten the
receptacle by the mounting screws to the utility box whereby the
ears of the receptacle overlap and firmly abut against the adjacent
outer wallboard surface, thereby attempting to stabilize the
receptacle. Attachment of the appearance cover plate will tend to
further stabilize the receptacle if the cover plate, when
threadably attached to the receptacle, is in firm contact with the
surrounding wall surface. Often, the end result of such an
installation is that, although it will visually pass inspection,
the receptacle is not firmly fixed and will rock or shift slightly
relative to the utility box when an appliance plug is inserted into
the receptacle or withdrawn from it.
Utilization of a pair of the devices 10 as shown in FIG. 2 provides
a firm adjustable mounting arrangement for an electrical fitting,
such as a receptacle or switch, to a junction box, with each device
10 acting a deformable shim to complete a firm attachment.
In its configuration shown in FIG. 2, the device 10 is formed in a
box-like shape and provided with a central passage to enable it to
be slidably placed on the fitting mounting screw, for installation
between the ear of the fitting and the tab of the junction box.
When the flat blank shown in FIG. 1 is folded along the indicated
break lines to form the configuration of the device 10 shown in
FIG. 2, holes 30 and 32 come into alignment with slot 28 to form a
central passage through the device for insertion therethrough the
flank of the mounting screw with the opposed outer surfaces of
sections 24 and 26 serving as flat bearing surfaces against which
compressive force will be applied during the installation
procedure. In its formed configuration as shown in FIG. 2, the
central section 22 extends diagonally between opposite edges of the
two bearing surfaces. Opposite sides of the device 10 are formed by
the legs 38 and 40 on one side, and 42 and 44 on the opposite side.
Each pair of adjacent legs are arcuately formed to provide a
concave shape, with the distal ends of the legs in contact with the
surface of the section 22. Each adjacent pair of these legs
constitutes a deformable flange which contributes to the elastic
resistance to compression of device 10, a characteristic which in
turn contributes to the stabilization of the connection of the
fitting to the utility box as hereto described.
The device 10 is intentionally designed and configured whereby the
dimension taken from the axis of its central screw passage and
across the outer face of either of sections 24 and 26 to any of the
straight bordering edges is no greater than the distance taken
radially from the center of the ear mounting hole (such as 66 in
FIG. 2) to the body 67 of the fitting or receptacle 60.
Accordingly, the lateral expanse of the device 10 (or of any other
embodiment of the invention herein described) is such that the
electrician need not be concerned with any particular rotational
orientation so long as the device is disposed on the mounting screw
and between the ear of the receptacle and the tab of the utility
box. For example, FIG. 3 shown a shim device 10 in its operative
position in a typical installation with the flange formed by legs
38 and 40 oriented upwardly and the flange formed by legs 42 and 44
oriented downwardly. The shim device 10 would serve its intended
purpose just as well if it happened to be installed in a rotated
position on the screw 70, as shown in FIG. 3.
The primary purpose of FIG. 3 is to illustrate the manner in which
the device 10 is capable of achieving firm securement of the
receptacle 60 in its mounted attachment to the box 50. The box 50
is shown mounted whereby its forward peripheral edge, defining its
open face through which the body of the receptacle 60 is inserted,
is misaligned with the outer surface of wallboard 78. The device 10
is utilized between the ear 62 and the tab 52 as a shim or spacer
capable of elastic deformation in response to rotative installatin
of the screw 70. Utilization of a pair of the device 10 on the
upper and lower mounting screws (only one of which is shown in FIG.
3) provides a means of quickly attaining a firm attachment between
the box 50 and the receptacle 60. This firm attachment will occur
even if the opening in the wallboard 78 to accommodate the
installation is oversized whereby the ear 62 (and the opposite ear
64) of the receptacle 60 make no contact whatsoever with the outer
surface of the wallboard.
Having described the characteristics and function of the embodiment
of the invention shown in FIGS. 1-3, attention is directed to an
alternative form of the invention shown in FIGS. 4A and 4B. FIG. 4A
shows an alternative shim device 80 in accordance with the present
invention which initially is a blank form 82 having transverse
break lines 84, 86, 88, and 90. The break lines 84 and 88 define an
intermediate section 92. Break lines 84 and 86 define between them
a section 94, and break lines 88 and 90 define between them a
section 96. Through the intermediate section 92 is an elongated
slot 98. Another elongated slot 100 opens outwardly at one end of
the blank 82 and a comparatively shorter slot 102 is provided at
the opposite end.
FIG. 4B shows the blank 82 properly folded along the aforementioned
break lines to form a configuration similar to the device 10 shown
in FIG. 1 except that the slots 98 and 100 cooperate to provide a
side opening to enable the device 80 to be installed to its
operative position after the receptacle mounting screws, such as 70
and 72 in FIG. 1, have already been installed in position through
the mounting holes 66 and 68 and into the threaded holes 5l and 58
of the box 50. Device 80, as shown in FIG. 4B, enables the
electrician to complete its installation from a side or lateral
position onto the shank of the mounting screw or to remove or
replace it while the mounting screw is threadably engaged into its
accommodating tab hole of the box 50.
FIG. 5 shows still another embodiment of structure in accordance
with the present invention capable of accomplishing the same
function as heretofore described with reference to devices 10 and
80. Specifically, FIG. 5 shows a utility box 110, of the molded
plastic type, having threaded screw sockets 112 and 114. A
receptacle 116 is illustrated as having oppositely extending ears
118 and 120. The ears have respective mounting holes 121 and 122 to
accommodate mounting screws 124 and 126.
For disposition between the respective ears 118 and 120 and the
utility box 110, a pair of shim devices 130 is provided. Each shim
device 130 has oppositely facing bearing surfaces, although only
the bearing surface 132 is visible in FIG. 5. Each of the bearing
surface has a central hole, as illustrated by hole 134, which are
aligned to accommodate extension therethrough of the mounting screw
shank. Opposite sides 136 and 138 of the device 130 are inwardly
sloped in an arcuate configuration whereby pressed deformation of
the device 130 between the ear 118 and the box 110 will cause the
side 136 to deform inwardly toward the screw shank as the bearing
surfaces are forced toward each other.
In forming the device 130, a long length of tubular metal stock may
be used having spring steel or elastic characteristics and the
desired configuration may be formed in the tubular stock by
extrusion. The extrusion can then be "chopped" into a plurality of
the devices 130. It is recognized that a suitable shim device,
capable of accomplishing the purpose of the invention, can be
obtained without the provision of the inwardly curved sides 136 and
138 whereby the device would be circular in cross-section. This
form, however, will result in outward deformation of the device
body, as it is compressed and deformed, to a generally elliptical
cross-section which ultimately can bind against the body of the
receptacle. Hence, the preference for the inward provided by the
inwardly curved sides 136 and 138.
It should be noted with respect to the device 130 that the
dimension of the device body taken normal to the axis of the hole
134 should be limited whereby the device 130 can be utilized in a
position rotated 90.degree. from that shown in FIG. 5 without
binding against the surface of the body of the receptacle, thus not
requiring that the device 130 be specially oriented so long as it
is properly placed in its operative disposition between the
receptacle ear and the utlity box, and on the shank of the mounting
screw.
If desired, the device 130 shown in FIG. 5 can be appropriately
slotted from each of its mounting holes and across the bearing
surfaces in the same direction to open at one end thereof whereby
the device 130 would be installable from a lateral or side position
onto the shank of the mounting screw, in the same manner as the
installation provided for the device 80 shown in FIG. 4B.
FIG. 6 of the drawing shows a fitting in the form of a receptacle
140 having modified upper and lower ears 142 and 144 which
incorporate, as an integral part of an electrical fitting, the
inventive concept herein disclosed. The ear 142 is shown as having
an outwardly facing surface or central section 146 defining a
mounting hole 148. The ear 142 further has rearwardly extending and
inwardly turned integral extension 150 and 152 which at their
terminus are slightly spaced apart to define them an open space
154. The structure and configuration of ear 144 is identical to
that of ear 142. The specially formed ears 142 and 144 which are
integral to the fitting 140 will accomplish the elastically
deformable shimming effect heretofore described in reference, for
example, to the device 10 shown in FIG. 2, except that here, in
FIG. 6, the shimming device is provided as an intergal part of the
fitting.
FIG. 7 illustrates a simplified embodiment of the present invention
in the form of a shim clip 160 having a V-shaped body presenting
spaced-apart legs 162 and 164, with a slot 166 provided centrally
in the apex of the V-shaped body and merging with respective
circular apertures 168 located centrally in the legs 162 and 164.
The slot 166 can be best visualized as two open-bottom keyhole
slots merging at the bend from which the legs project.
The device 160 can be utilized in the same manner as heretofore
described with respect the the device 80 shown in FIG. 4B, since it
is adapted to be used as a deformable shim between the fitting ear
and the tab or socket of a utility box and can be mounted in a
lateral sliding action onto the shank of a mounting screw already
in position. The outer surfaces of the legs 162 and 164 serve as
bearing surfaces for abutting contact, respectively, with the area
of the utility box defining the mounting screw socket and the
inside surface of the ear of the fitting to be mounted in the
box.
The slot 168 serves as a means of sliding the clip 160 laterally
onto the shank of a fittig mounting screw, in the same general
manner as heretofore described with regard to device 80 shown in
FIG. 4B. Each of the opposite openings, such as 168, has a diameter
substantially that of the outside diameter of the shank of the
typical receptacle mounting screw, and a narrow neck area 170 is
sufficiently wide to enable the clip to be forceably pushed onto
the screw shank but is sufficiently narrow to resist removal or
dislodgement of the clip from its mounted operational position on
the screw shank. In use, the legs 162 and 164 of the clip 160 are
forced toward each other when the mounting screw is threadably
rotated into its engagement with the utility box to draw the
receptacle into position. The elastic or spring characteristic of
the clip renders it resistant to the squeezing deformation.
Where, in a particular installation, the utility box is mounted
rearwardly from the wall surface an unusual distance, it may be
beneficial to employ a plurality of the shim clips 160 on each
mounting screw. In this regard, where the angle of the leg 162 to
the leg 164 is maintained at 45.degree., then a pair of the shim
clips 160, positioned together on a mounting screw, will form a
rectilinear unit in the sense that the outer leg of each clip in
the pair will constitute a transversely extending bearing surface
substantially as described with reference to the surfaces 24 and 26
of the device 10 shown in FIG. 2.
While various embodiments of the present invention have been
heretofore described and illustrated in the accompanying drawings,
it is to be understood that other embodiments or variations may be
made with benefit of the teachings herein and without departing
from the spirit and scope of the invention, and that all such
embodiments and equivalent variations are intended to be included
within the scope of the appended claims.
* * * * *